Quinn Kennedy

Cognitive and Noncognitive Symptoms in Dementia Patients: Relationship to Cortisol and Dehydroepiandrosterone

We investigated the relationship between basal cortisol and dehydroepiandrosterone (DHEA) levels and impairment in different cognitive and noncognitive measures and the possible interaction of DHEA with hypercortisolemia in dementia in 27 patients diagnosed with Alzheimers disease (AD). There were 17 men and 10 women. Patients were mildly to moderately cognitively impaired at the time of the initial cortisol measures. Patients were administered the Alzheimers Disease Assessment Scale (ADAS) and Folstein Mini-Mental State Examination (MMSE) at approximately 6-month intervals. Cortisol and DHEA were determined using conventional 125I radioimmunoassay procedures. Pearson product-moment correlations among cortisol and DHEA measures and both initial and longitudinal clinical measures were calculated. There was a relationship between baseline 8 a.m. cortisol levels and cognitive function at the initial testing as measured by the ADAS cognitive measure, with higher cortisol levels being associated with a greater level of impairment. We did not document a relationship between cortisol or DHEA levels and noncognitive measures. There was a significant correlation between both the initial MMSE and ADAS cognitive measures and initial DHEA level, with lower DHEA levels unexpectedly being associated with better performance on these measures. The initial DHEA levels did not predict decline in cognitive function over time. These findings bring into question the potential usefulness of DHEA as a therapeutic agent.

Training Simulation for Helicopter Navigation by Characterizing Visual Scan Patterns

INTRODUCTION Helicopter overland navigation is a cognitively complex task that requires continuous monitoring of system and environment parameters and years of training. This study investigated potential improvements to training simulation by analyzing the influences of flight expertise on visual scan patterns. METHODS There were 12 military officers who varied in flight expertise as defined by total flight hours who participated in overland navigation tasks. Their gaze parameters were tracked via two eye tracking systems while subjects were looking at out-the-window (OTW) and topographic Map views in a fixed based helicopter simulator. RESULTS Flight performance measures were not predicted by the expertise level of pilots. However, gaze parameters and scan management skills were predicted by the expertise level. For every additional 1000 flight hours, on average, the model predicted the median dwell will decrease 28 ms and the number of view changes will increase 33 times. However, more experienced pilots scanned more OTW than novice pilots, which was contrary to our expectation. A visualization tool (FEST: Flight and Eye Scan visualization Tool) to replay navigation tasks and corresponding gaze data was developed. Qualitative analysis from FEST revealed visual scan patterns of expert pilots not only looking ahead on the map, but also revisiting areas on the map they just flew over to retain confidence in their orientation. DISCUSSION Based on the analysis provided above, this work demonstrates that neurophysiological markers, such as eye movements, can be used to indicate the aspects of a trainees cognitive state that are useful for cuing an instructional system.

The child abuse potential inventory and pregnancy outcome in expectant adolescent mothers

OBJECTIVE The study explores the prenatal Child Abuse Potential (pCAP) scores derived from the Child Abuse Potential Inventory administered to expectant adolescent mothers. The aim of the study was to assess the association of the pCAP scores with maternal negative prenatal behaviors, and evaluate the contribution of the pCAP scores to neonatal morbidity. METHOD The pCAP scores, demographic data, and self-report on prenatal behaviors were obtained during the second half of the pregnancy in a sample of 45 poor single adolescent mothers. A pediatrician blind to the prenatal data reviewed the neonatal records to assess neonatal morbidity. Maternal prenatal records were reviewed for obstetric risk assessment by an obstetrician who was blind to the rest of the data. The relations among the pCAP scores, prenatal behaviors, and neonatal morbidity were analyzed. RESULTS In the prenatal period, the pCAP scores were positively correlated with self-reported prenatal smoking and substance use. The multiple linear regression analysis showed that the pCAP scores significantly contributed to neonatal morbidity independently of obstetric risk factors. CONCLUSIONS The Child Abuse Potential scores obtained during pregnancy in poor single adolescent mothers reflect domains of maternal functioning that are associated with negative prenatal behaviors and appear to be important for predicting neonatal morbidity. Further studies are warranted to validate the prenatal use of the Child Abuse Potential Inventory.

Identifying and addressing the limitations of safety climate surveys

INTRODUCTION There are a variety of qualitative and quantitative tools for measuring safety climate. However, questionnaires are by far the most commonly used methodology. METHOD This paper reports the descriptive analysis of a large sample of safety climate survey data (n=110,014) collected over 10 years from U.S. Naval aircrew using the Command Safety Assessment Survey (CSAS). RESULTS The analysis demonstrated that there was substantial non-random response bias associated with the data (the reverse worded items had a unique pattern of responses, there was a increasing tendency over time to only provide a modal response, the responses to the same item towards the beginning and end of the questionnaire did not correlate as highly as might be expected, and the faster the questionnaire was completed the higher the frequency of modal responses). It is suggested that the non-random responses bias was due to the negative effect on participant motivation of a number of factors (questionnaire design, lack of a belief in the importance of the response, participant fatigue, and questionnaire administration). CONCLUSIONS Researchers must consider the factors that increase the likelihood of non-random measurement error in safety climate survey data and cease to rely on data that are solely collected using a long and complex questionnaire. IMPACT ON INDUSTRY In the absence of valid and reliable data it will not be possible for organizations to take the measures required to improve safety climate.

Intraindividual Variability in Basic Reaction Time Predicts Middle-Aged and Older Pilots’ Flight Simulator Performance

OBJECTIVES Intraindividual variability (IIV) is negatively associated with cognitive test performance and is positively associated with age and some neurological disorders. We aimed to extend these findings to a real-world task, flight simulator performance. We hypothesized that IIV predicts poorer initial flight performance and increased rate of decline in performance among middle-aged and older pilots. METHOD Two-hundred and thirty-six pilots (40-69 years) completed annual assessments comprising a cognitive battery and two 75-min simulated flights in a flight simulator. Basic and complex IIV composite variables were created from measures of basic reaction time and shifting and divided attention tasks. Flight simulator performance was characterized by an overall summary score and scores on communication, emergencies, approach, and traffic avoidance components. RESULTS Although basic IIV did not predict rate of decline in flight performance, it had a negative association with initial performance for most flight measures. After taking into account processing speed, basic IIV explained an additional 8%-12% of the negative age effect on initial flight performance. DISCUSSION IIV plays an important role in real-world tasks and is another aspect of cognition that underlies age-related differences in cognitive performance.

Initial Cognitive Performance Predicts Longitudinal Aviator Performance

OBJECTIVES The goal of the study was to improve prediction of longitudinal flight simulator performance by studying cognitive factors that may moderate the influence of chronological age. METHOD We examined age-related change in aviation performance in aircraft pilots in relation to baseline cognitive ability measures and aviation expertise. Participants were aircraft pilots (N = 276) aged 40-77.9. Flight simulator performance and cognition were tested yearly; there were an average of 4.3 (± 2.7; range 1-13) data points per participant. Each participant was classified into one of the three levels of aviation expertise based on Federal Aviation Administration pilot proficiency ratings: least, moderate, or high expertise. RESULTS Addition of measures of cognitive processing speed and executive function to a model of age-related change in aviation performance significantly improved the model. Processing speed and executive function performance interacted such that the slowest rate of decline in flight simulator performance was found in aviators with the highest scores on tests of these abilities. Expertise was beneficial to pilots across the age range studied; however, expertise did not show evidence of reducing the effect of age. DISCUSSION These data suggest that longitudinal performance on an important real-world activity can be predicted by initial assessment of relevant cognitive abilities.

Bayesian modeling of pilot belief and visual misperception in helicopter overland navigation

This paper aims to provide a framework to model human belief and misperception in helicopter overland navigation. Helicopter overland navigation is known to be a challenging cognitive task, and understanding the cognitive processes associated with it is non-trivial. Twelve military personnel participated in the study and statistical analysis showed that their gaze parameters can be predicted by their level of expertise. Some pilots showed common visual misperception during the navigation task, which can be explained by the following errors: 1) confusion between inference and evidence, 2) incorrect mutually exclusive assumptions on the data, and 3) biased sampling. Simulation results on two cases observed in the experiments are given. Quantitative differences in dynamic perceptions between a Bayesian agent and misperceiving humans are presented with the suggested modeling framework.

The impact of brain size on pilot performance varies with aviation training and years of education

Previous studies have consistently reported age-related changes in cognitive abilities and brain structure. Previous studies also suggest compensatory roles for specialized training, skill, and years of education in the age-related decline of cognitive function. The Stanford/VA Aviation Study examines the influence of specialized training and skill level (expertise) on age-related changes in cognition and brain structure. This preliminary report examines the effect of aviation expertise, years of education, age, and brain size on flight simulator performance in pilots aged 45-68 years. Fifty-one pilots were studied with structural magnetic resonance imaging, flight simulator, and processing speed tasks. There were significant main effects of age (p < .01) and expertise (p < .01), but not of whole brain size (p > .1) or education (p > .1), on flight simulator performance. However, even though age and brain size were correlated (r = -0.41), age differences in flight simulator performance were not explained by brain size. Both aviation expertise and education were involved in an interaction with brain size in predicting flight simulator performance (p < .05). These results point to the importance of examining measures of expertise and their interactions to assess age-related cognitive changes.

Lack of Association Between COMT Polymorphisms and Apathy in Alzheimer's Disease

We tested the hypothesis that single nucleotide polymorphisms (SNPs) in catechol-O-methyltransferase (COMT) are associated with apathy in individuals with Alzheimers disease (AD). We analyzed a cohort of 105 Caucasian individuals with AD (age = 79.3 ± 7.03 years; MMSE = 20.2 ± 4.4) according to the presence of apathy, as defined either by the Neuropsychiatric Inventory or the Apathy Inventory. Polymorphisms in seventeen SNPs in COMT were examined. A replication cohort consisting of 176 Caucasian AD subjects in the ADNI database was also analyzed. None of the candidate gene SNPs were significantly associated with the presence of apathy in either cohort. We did not find any SNPs in COMT that were consistently associated with apathy in individuals with AD.

Helicopter Pilot Misperception and Confidence During Overland Navigation

This paper aims to provide insights into human perception, navigation performance and confidence in helicopter overland navigation. Helicopter overland navigation is a challenging mission area because it is a complex cognitive task, and failing to recognize when the aircraft is off-course can lead to operational failures and mishaps. A human-in-the-loop experiment to investigate pilot misperception during simulated overland navigation by analyzing actual navigation trajectory, pilots’ perceived location, and corresponding confidence levels was designed. Fifteen military officers with prior overland navigation experience completed four simulated low-level navigation routes, two of which entailed auto-navigation. Analysis shows that there is no correlation between perceived and actual location of the aircraft, nor between confidence level and actual location. There is however some evidence that there is a negative correlation between perceived location and intended route of flight, suggesting that there is a bias towards that intended flight route. If aviation personnel can proactively identify the circumstances in which usual misperception occur in navigation, they may reduce mission failure and mishap rate. Fleet squadrons and instructional commands can benefit from this study to improve operations that require low-level flight while also improving crew resource management.